Hey guys,I've got an 86 GMC pu with a 4.3.It doesn't have any power accesories.It does have a smog pump.I've heard that they are pretty inefficient and wondered what you guys thought.I was planning on removing it and welding up the hoses.Anything to gain a little more power.
you'll gain 1/10th of a HP and pollute the atmosphere. They are so insignificant. They inject air into the exhaust, so they don't affect power, other than the tiny amount it takes to spin the vane-style pump.
Seriously. If you want to gain HP, the smog pump is NOT the way to do it. Fix the abyssmal compression, tiny cam, and electronically controlled carb, but I guarantee that you won't gain any measurable HP by removing the smog pump, but you will be responsible for increasing your HC emissions by about sevenfold. If you have a cat, make sure you remove it because without the air pump it will clog very soon. If you remove the cat you will gain 1 or 2 hp and increase your NOx emissions by about tenfold.
Why do people assume that smog equipment is responsible for all this magic HP?
I really didn't know that they did that much to affect emissions. Smog pumps are heavy and can be pricey to replace if the unit isn't working properly. I doubt that you would gain more than 1 hp by deleting it. If it's still in good condition, I guess I would keep it on.
Thanks Curtis.It doesn't have a comp controlled carb.I figured someone had changed it but I looked up the #s and they arer correct.I'm going to install a MSD and dual exhaust soon.I just had always heard that the 70s and 80s smog pumps were pretty well junk and didn't really do much.It works and doesn't bother me to leave it. :thumbup:
they actually take a little more than 1 hp- closer to about 3, but yea, its no magic power restricter. A set of long tube headers and some ported heads would be the best way to wake it up for little $. Beyond that you're best switching to a SBC.
Hey ap72,what fun would swapping in a SBC be? The engine runs great and I was just looking to get rid of anything that doesn't need to be there.I have found some shorty headers for later model pu's but havn't seen any long tubes.I don't really want to pull the heads because this a daily driver.I might try to find a set at Pick and Pull and work them over.So as not to be tore down to long. :mwink:
Hey ap72,what fun would swapping in a SBC be? The engine runs great and I was just looking to get rid of anything that doesn't need to be there.I have found some shorty headers for later model pu's but havn't seen any long tubes.I don't really want to pull the heads because this a daily driver.I might try to find a set at Pick and Pull and work them over.So as not to be tore down to long. :mwink:
Excellent idea! you should be able to get them for around $50. Spend some time on the bench with them and upgrade your valves, springs, and rockers while you're at it. You'd be looking at about $300 not including a valve job or milling- if you elected to do that too. Of course the next thing would be a cam swap.... and then it snowballs...
Before you go tearing things out, consider their benefits first. For instance, the engine will run fine without a PCV valve, but it doesn't cost any HP and it nearly triples your oil life which has HUGE benefits for engine longevity. You can remove the EGR, but again, it doesn't cost any HP and has huge benefits (both from emissions and MPG) if you leave it there. The smog pump thing has been tested a few million times on a dyno, and there is nothing there to suggest any gains of more than 1 hp... and you'll never feel 1 hp. You probably wouldn't even be able to feel 10 hp.
People blame emissions for all the HP problems of the world, but they really aren't the problem. I suggest you leave it intact until it becomes a problem. With the exception of the catalyst, all that emissions stuff helps your MPG, cleans up pollution by as much as 90%, extends oil life, extends engine life, and doesn't cost more than 1-2 hp.
You would do well to heed the advice of curtis73. Fiddling with a 4.3 in a pickup to try to get more power is like asking a boy to do a man's job. There's plenty of room in there for a 454.
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